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Introduction

The aim of this C# project is to purpose six aircraft cockpit instruments usable in forms as any other C# controls and to define a generic instrument class in order to design any kind of dashboard instuments.

Description

The controls are built with bitmaps which are rotated, translated or scaled before to be displayed. The basic methods for rotate, translate and scale images are defined in the mother class. Each control then uses his dedicated parameters (related to a physical signification) in order to manipulates the images .

Aircraft instruments

Air speed indicator : airspeed (kts)

Attitude Indicator : pitch (deg), roll (deg)

Altimeter : altitude (ft)

Turn Coordinator : turn rate (deg/min)

Vertical speed indicator : vertical speed (ft/min)

Heading indicator : heading (deg)

Details of the key functions

This section explains in details the implementation of the basic functions defined in the InstrumentControl class.

Rotate Image

Implementation

The rotation of the image is divided in two main part:

First : the rotation of the PaintEventArgs coordinate system around the upper left corner of the drowing area.

Second : the drowing of the image corrected by translation offset in order to display the image as if it has turned around a user defined point

AvionicsControlDemo_RotationMainSteps.JPG

Let’s see step by step

Step 0 : initial situation.

AvionicsControlDemo_RotationPhase0.JPG

Step 1 : Rotate the PaintEventArgs coordinate system around the left upper corner of the paint area.

AvionicsControlDemo_RotationPhase1.JPG

Corresponding code sample:

// Rotate image support
pe.Graphics.RotateTransform((float)(alpha * 180 / Math.PI));
 

Step 2 Draw the image and applies the translation correction.

AvionicsControlDemo_RotationPhase2.JPG

Corresponding code sample :

// Dispay image
pe.Graphics.DrawImage(img, (ptImg.X + deltaX) * scaleFactor, (ptImg.Y + deltaY) * scaleFactor, img.Width * scaleFactor, img.Height * scaleFactor); 

Step 3 (Final step ) : Put the PainEventArgs coordinate system as found.

AvionicsControlDemo_RotationPhase3.JPG

Corresponding code sample :

// Put image support as found
pe.Graphics.RotateTransform((float)(-alpha * 180 / Math.PI));


The key point in those operations is the calculation of the translation correction coefficients.

The next figure explain the geometrics considerations.

AvionicsControlDemo_RotationDetailedScheme.JPG

G0 is the user defined rotation center
G1 is the G0 position after the step 1.

The aim of this section is to identified the G1G0 translation and applied the corresponding offset in order to draw the rotation point as if it has not moved.

Then we work with the geometrics definitions:

a)

AvionicsControlDemo_RotationCalcs1.JPG

b)

AvionicsControlDemo_RotationCalcs2.JPG

c)

AvionicsControlDemo_RotationCalcs3.JPG

d)

AvionicsControlDemo_RotationCalcs4.JPG

As a result the offset coefficients are :

AvionicsControlDemo_RotationCalcs5.JPG


Corresponding code sample :

  // Computed offset
deltaX = (float)(d * (Math.Cos(alpha - beta) - Math.Cos(alpha)* Math.Cos(alpha + beta) - Math.Sin(alpha) * Math.Sin(alpha+ beta)));
deltaY = (float)(d * (Math.Sin(beta - alpha) + Math.Sin(alpha)* Math.Cos(alpha + beta) - Math.Cos(alpha) * Math.Sin(alpha + beta)));

Parameters


"pe" :The paint area event where the image will be displayed
"img" :The image to display
"alpha" :The angle of rotation in radian
"ptImg" :The location of the left upper corner of the image to display in the paint area in nominal situation
"ptRot" :The location of the rotation point in the paint area
"scaleFactor" : Multiplication factor on the display image

AvionicsControlDemo_RotationFunctionParameters.JPG

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7:25 28 Oct '09  
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21:09 24 Feb '09  
GeneralAdd to projects Pin
Frank Shearer
15:28 20 Feb '09  
GeneralTransform Pin
NicolasG
11:59 25 Jul '08  
GeneralRe: Transform Pin
DrGanjoo
0:08 12 Nov '08  
GeneralExcellent look and feel to these controls - well done Pin
BradOsterloo
13:05 21 Jul '08  
GeneralCool! Pin
bigals
14:55 20 Jul '08  
GeneralFantastic job.... But there is something missing... Pin
The Infomercial King
8:11 18 Jul '08  
GeneralRe: Fantastic job.... But there is something missing... Pin
andre12345
9:53 18 Jul '08  
GeneralRe: Fantastic job.... But there is something missing... Pin
The Infomercial King
10:55 18 Jul '08  
GeneralAH for 90 degree pitch Pin
jknickel
1:24 8 Jul '08  
GeneralRe: AH for 90 degree pitch Pin
Chootair
12:59 17 Jul '08  
GeneralGreat stuff Pin
jknickel
23:54 7 Jul '08  
GeneralSuperb but... Pin
Joe Sonderegger
23:01 7 Jul '08  
GeneralGreat work.... Pin
Peter Villadsen
15:33 7 Jul '08  
GeneralRe: Great work.... Pin
Chootair
13:03 17 Jul '08  
JokeImpressive Pin
Ivertheengine
10:32 7 Jul '08  
GeneralWow! Pin
Rafferty Uy
16:48 3 Jul '08  
GeneralVery nice indeed. Question... Pin
thompsons
7:42 2 Jul '08  
GeneralVery Good Pin
JBAK_CP
4:41 2 Jul '08  
GeneralRemarkable! Pin
LastZolex
0:15 2 Jul '08  
GeneralExcellento! Pin
Tage Lejon
22:08 1 Jul '08  
GeneralThis could be very cool Pin
Bert delaVega
18:28 1 Jul '08  
GeneralAlitmeter Pin
sgenie68
15:17 1 Jul '08  


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